Thales, an ancient Greek philosopher, looked up at the starry sky to predict rain, but he didn't look at his feet and fell into the pit. People take this opportunity to ridicule philosophers for being unrealistic and just empty talk. Hegel said: "a nation has some people who care about the sky, so they have hope;" A nation only cares about what is under its feet, and that has no future. " At the same time, he added: "only those who lie in the pit forever and never look up at the sky will not fall into the pit." "Only those who lie in the pit and don't look up at the heights will have no future. In other words, looking up at the stars, even though they may fall into the pit, those who look up have gained wisdom and hope; And those who only bury themselves in worldly things and don't know how to look up at the stars to seek true knowledge will never fall even if they lie in the pit of the earth, but will only be trapped in the pit forever, without wisdom and hope for development.